Appabatus fob automatically deter



Sept. 19, 1939. o, msz o Re. 21,210

APPARATUS FOR AUTOMATICALLY DETERMINING THE EXPOSURE IN PHOTOGRAPHIC APPARATUS Original Filed Jan. 28, 1931 3 5neetsSheet 1 Sept. 19, 1939. Q RISZDORFER Re. 21,210

APPARATUS FOR AUTOMATICALLY DETERMINING THE EXPOSURE IN PHOTOGRAPHIC APPARATUS Original Filed Jan. 28, 1931 3 Sheets-Sheet 2 Sept. 19, 1939. Q msz F Re. 21,210

APPARATUS FOR AUTOMATICALLY DETERMINING THE EXPOSURE IN PHOTOGRAPHIC APPARATUS Original Filed Jan. 28, 1931 5 Sheets-Sheet 3 IIIIII r g f l 42 u INVENTOR' I I 4 1' W 0- 513; ciorfe;

I TORNEYS.

Reissued Sept. 19, 1939 UNITED STATES APPARATUS FOR AUTOMATICALLY DETER- MINING THE EXPOSURE IN PHOTO- G RAPHIC APPARATUS Odiin Biszdorier, Budapest, Hungary Original No. 2,000,037, dated May 7, 1935, Serial January 28, 1931. Application for reissue September 25, 1936, Serial No. 102,812

15 Claim.

This invention relates to apparatus for determining the correct exposure in photographic cameras and like apparatus.

The invention has for its object to enable the correct exposure to be determined at all times in a simple manner without involving errors of observation such as may occur in the case of optical exposure meters.

The quantity of light which impinges on the light-sensitive emulsion during a photographic exposure is determined by the size of the diaphragm opening of the photographic objective and by the time during which the objective is uncovered, that is to say, by the speed of the shutter. The diaphragm opening is usually adjustable and the shutter adjustable for obtaining different speeds. Owing to this, there is some difficulty in the case of any particular exposure of choosing a. diaphragm stop and shutter speed such that correct exposure of the light-sensitive layer takes place.

This difliculty is overcome by means of the present invention which consists in the provision on the camera of a photo-electric cell fitted with an adjustable diaphragm, the said cell being included in an electric circuit containing a movable indicating member actuatable by'the cell current, said indicating member co-operating with a second indicating member, manually actuatable means being provided for varying the position of one of the indicating members adjusting means of which is positively interconnected relatively to the other for enabling the indicating members to be brought into coincideuce, said manually actuatable means being positively connected to one of the adjustable exposure controlling devices, viz., diaphragm or shutter, which control the passage of light through the objective, so that when the indicating members are adjusted to bring them into coincidence the said exposure controlling device is adjusted in accordance with the displacement of the indicating member actuated by the cell current.

Adjustment of the diaphragm of the photoelectric cell varies the quantity of light passing to the photo-electric cell and consequently the current which flows through the electric circuit so that the position of the indicating member which is actuatable by the cell current will be altered every time the diaphragm of the photoelectric cell is adjusted.

In cases where only the exposure controlling device connected to the means for establishing coincidence is adjustable, while the other exposure controlling device is non-adjustable (single speed shutter or single stop diaphragm), the diaphragm of the photo-electric cell need only be varied when a faster or slower sensitive layer is employed. -n the other hand when both the shutter and the ably positively interconnected.

The accompanying drawings show several con-' structional forms of the invention by way of example.

Fig. 1 shows a view of an arrangement according to the invention, and

Fig, 2 shows a view of a modification of the arrangement shown in Fig. 1.

Fig. 3 shows a tooth gear mechanism for adjusting the diaphragm of the objective.

Fig. 4 shows an arrangement corresponding to Fig. 1, the shutter operating mechanism being adjusted, however, instead of the diaphragm.

Fig. 5 shows an arrangement according to Fig. 2 but with the shutter adjusting means connected up to the diaphragm oi the photo cell.

In the arrangement shown in Fig. 1, the iris diaphragm of the objective of a photographic apparatus is indicated by II. The mounting i2 of the diaphragm is constructed as a worm wheel into the teeth of which the worm l3 engages. The worm I3 is mounted in bearings l4 and I5 and the upper end of the shaft l6 of the worm is provided with knob l1 adapted to be actuated by hand. 0n the shaft ii there is: attached in addition an indicator it which lies above or below the finder glass I9 and the position of which at a given instant corresponds to the degree of rotation of the shaft 16 and therefore to the size of the aperture of the diaphragm H. 20 is a photoelectric cell which may likewise be provided with a diaphragm 2|. The mount 22 of the diaphragm is constructed as a toothed wheel and engages with the disc 23 which is likewise constructed as a toothed wheel and which is the disc usually provided in photographic apparatus for adjusting the speed of the shutter 23i of the objective. A coil 25 is situated in the circuit 24 of the photo-cell, within which coil a soft iron core 26 is capable of rotating, as in the case of measuring instruments. The soft iron core 26 has a hollow shaft 21 which is mounted at 28 and 29 and which carries an indicator 30. The indicator 30 also moves above or below the finder glass or the matt plate [9 coaxially'with the indicator I8 since the shaft [6 of the indicator l8 passes through the hollow shaft 21.

Before photographing, the circuit 24 of the cell current is closed by means of a switch 3|, whereupon the battery 32 yields current. The shutter is then adjusted to the desired speed by rotating the disc 23. The connection between the disc and the diaphragm 2| of the cell is such that the greater the speed chosen the more the aperture of the diaphragm ii is diminished. A current of strength corresponding to the illumination of the photo-cell Ill is set up in the circuit 24 and the indicator 30 is deflected from the zero (0) position. The knob i1 is now rotated until the indicator l8 coincides with the indichosen each time being taken into consideration I by the adjustment of the diaphragm 2! by means of disc 25.

The plate sensitivity, so far as it deviates from the normal, may likewise be taken into account by arranging the diaphragm ll of the photocell so as to be adjustable also by hand and, after adjusting the speed of the shutter, correcting the diaphragm aperture by hand in addition.

Instead of having two movable indicating members It and 55 the same problem may also be solved with one movable and one stationary indicating member. Such a construction is shown in Fig. 2. In this construction the indicator 54 is likewise moved by the cell current as already described for Fig. 1. The second indicating member is a line II on the matt plate or in the finder. In the cell circuit 35 there is a variable resistance 35, over the contacts 51 of which the sliding contact 55 moves. The latter is carried by the travelling nut 55 which travels along the guide 4! when the spindle 45 is rotated. The spindle 40, capable of being rotated by the hand wheel or knob 42, continues into the worm 45 which adjusts the objective diaphragm 45 by way of the screw wheel 44, just as already described in the case Of Fig. 1. The photocell 46, with the diaphragm 41, the switch 48. and the battery 45 are similarly arranged as in Fig. 1.

If switch 48 is closed the indicator 34 deflects. as shown, the deflection being proportional to the current strength in the circuit 35. The small wheel 42 is now rotated until the contact inserts as much resistance into the current circuit 35 as suffices to bring the indicator 34 back to the zero position. At the same time the objective dia-' phragm 45 is diminished by way of the worm 43, the diminution being the greater the greater is the deflection oi the indicator 34, and therefore the greater the current in the circuit 35. In this constructional form, therefore, there is also the same proportionality between the exposure of the photocell and the adjustment of the objective diaphragm as in the arrangement shown in Fig. 1.

Since the exposure of the plate decreases with the adjustment of the diaphragm in inverse proportion to the square of the diaphragm opening, the resistance 55 is preferably constructed in such a way, or the individual resistance stays are constructed in such a way, that the resistance of the successive stages are in quadratic ratio to one another. In this way linear proportionality between the cell current and the movements oi the adjusting mechanism 40, 43 is secured.

A constructional form is shown in Fig. 4 whichcorresponds substantially to the arrangement of Fig. l. The photocell 54 with the cell circuit." and the adjusting mechanism 55 are constructed in exactly the same manner as the corresponding members in Fig. l. The spindle 55 engages the disc 81 which is geared to the shutter. and adjusts the shutter speed. The diaphragm 55 of the photocell and the diaphragm 55 of the camera objective are positively connected together by gear teeth in a similar manner to the adjusting disc 23 ot the shutter shown in Fig. l. The apparatus operates in the same way as that oi Fig. 1 in that flrst 01' all by rotating the diaphragm 89 of the apparatus the diaphragm of the photocell is adjusted, after which as described in Fig. 1 the pointers are brought into coincidence and thereby the corresponding shutter speed is adjusted.

The fact that the intensity of illumination of the plate varies in proportion to the square of the diameter 0! the diaphragm can also be taken into account by inserting a suitable gear in the adjusting mechanism of the diaphragm. Such an arrangement is shown on Fig. 3. The indicator 55, movable above the finder glass 5i which latter carries a line representing the 0 mark, is fixed on the adjusting peg' 52. The adjusting peg 52 is rotatably supported in the bracket 55. The bracket 53 is flxed solidly on the photographic camera'and fltted with a slot serving as a straight line guide. Inside the slot 54 glides the sliding block 55 which is connected throus rods 55 and 51 with the toothed segment 58. The toothed segment 55 is pivoted on the solidly fixed pin 59 and engages with the toothing on the diaphragm frame 59. The adjusting peg is connected with the link ill, in which a curved slot BI is provided. The curvature oi the slot has been chosen so as to ensure that when the adjusting pin 52 is turned, the segment 55 or respectively the diaphragm 55 will effect movements of such magnitude as to make the intensity of illumination of the photographic plate vary in proportion to the movements. 0! indicator 50. In other respects the arrangement, notably the electrical adjusting mechanism for the indicator 52 and the arrangement of the photocell resembles that shown on Fig. l.

The constructional form shown in Fig. 5 cor- I responds substantially to the arrangement of Fig. 2 but the diaphragm 41 of the photocell 46 is positivelyconnected up to the speed adjusting member 23 of a variable speed shutter by gear teeth. so that when the shutter speed is adjusted, the

diaphragm of the photo cell is correspondingly adjusted. By this means. it the shutter speed is adjusted to a particular value. the correct diaphragm opening is obtained when the indicator 34 is brought into the zero position. On the other hand when it is desired to employ a particular stop number, after the diaphragm 45 has been suitably adjusted. it is'only necessary to adjust 1. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity or light passing through said objective, means for determining the correct exposure. comprising in combination a photo-electric cell having an adjustable dia-.

phragm for varying the quantity of light passing to the cell, two indicating members, one of said members actuatable by the cell current. manually actuatable means tor varying the position of one of said indicating members relatively to the other for enabling the indicating members to be brought into coincidence and positive transmission means connected to one of said exposure controlling devices so as to enable the said exposure controlling device to be adjusted .in accordance with the displacement oi the indicating member actuated by the cell current.

2. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing to said objective, means for determining the correct exposure, comprising in combination a photo-electric cell having an adjustable diaphragm for varying the quantity or light passing to the cell, a fixed indicating member, a movable indicating member actuatable by the cell current, manually actuatable means for varying the position of said movable indicating member relatively to the fixed indicating member for enabling the indicating members to be brought into coincidence and .positive transmission means connected to said manually actuatable means and to one of the said exposure controlling devices, so as to enable the said exposure controlling device to be adjusted in accordance with the displacement oi the indicating member actuated by the cell cur rent.

3. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing to said objective, means for determining the correct exposure, comprising in combination a photo-electric cell having an adjustable diaphragm for varying the quantity of light passing to the cell, a movable indicating member having electrical actuating means therefor operatively connected to the photo-electric cell so as to be capable of operation by the cell current, a second indicating member, manually actuatable regulating means for varying the strength of the cell current, for varying the position of said movable indicating member relatively to the other indicating member and positive transmission means connected to'said manually actuatable regulating means and to one of said exposure controlling devices, so as to enable the said exposure controlling device to be adjusted in accordance with the displacement of the indicating member actuated by the cell current.

4. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing to said objective, means for determining the correct exposure, comprising in combination a photo-electric cell having an adjustable diaphragm for varying the quantity of light passing to the cell, a movable indicating member having electrical actuating means therefor operatively connected to the photo-electric cell so as to be capable of operation by the cell current, a second indicating member, a manually actuatable variable resistance for varying the strength of the cell current, for varying the position of said movable indicating member relatively to the other indicating member and positive transmission means connectedto said variable resistance and to one of said controlling devices, so as to enable the said exposure controlling device to be adjusted in accordance with the displacement of the indicating member having electrical actuating means therefor.

5. In a portable photographic apparatus hav ing an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light'passing through said objective, means for determining the correct exposure, comprising in combination a photoelectric cell having an adjustable diaphragm for varying the quantity of light passing to the cell, said diaphragm operatively connected to one of said exposure controlling devices, two indicating members, one of said members actuatable by the cell current, manually actuatable means for vary? ing the position of oneoi' said indicating members relatively to the other for enabling the indicatlng members to be brought into coincidence and positive transmission means connected to said manually actuatable means and the other 01 the said exposure controlling devices so as to enable the said exposure controlling device to be adjusted in accordance with the displacement of the indicating member actuated by the cell current.

6. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing to said objective, means for determining the correct exposure, comprising in combination a photo-electric cell having an adjustable diaphragm for varying the quantity of light passing to the cell, said diaphragm operatively connected to one of said exposure controlling devices, a fixed indicating member, a movable indicating member actuatable by. the cell current, manually actuatable means for varying the position of said movable indicating member relatively to the fixed indicating member for enabling the indicating members to be brought into coincidence and positive transmission means connected to said manually actuatable means and to the other of the said exposure controlling devices, so as to enable the said exposure controlling device to be adjusted in accordance with the displacement of the indicating member actuated by the cell current.

'7. In a portable photographic apparatus having an objectiveand two exposure controlling devices, viz., a shutter and a diaphragm for. controlling the quantity of light passing to said objective, means for determining the correct exposure, comprising in combination a photo-elec-' tric cell having an adjustable diaphragm for varying the quantity of light passing to the cell, said diaphragm operatively connected to one of said exposure controlling devices, a movable indicating member having electric actuating means therefor operatively connected to the photo-electric cell so as to be capable of operation by the cell current, a second indicating member, manually actuatable regulating means for varying the strength of the cell current, for'. varying the position of said movable indicating member relatively to the other indicating member, and positive transmission means connected to said manually actuatable regulating means and to the other of said exposure controlling devices, so as to enable the said exposure controlling device to be adjusted in accordance with the displacement of the indicating member actuated by the cell current.

8. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing to said objective, means for determining the correct exposure, comprising in combination a photo-electric cell having an adjustable diaphragm for varying the quantity of light passingto the cell, said diaphragm operatively connected to one 01' said exposure controlling devices, a movable indicating member having electrical actuating means therefor operatively connected to the photo-electric cell so as to be capable of operation by the cell current, a second indicating member, a manually actuatable variable resistance for varying the strength oi the cell current, for varying the position of said movable indicating member relatively to the other indicating member and positive transmission means connected to said variable resistance and to the other oi said controlling devices, so as to enable the said exposure controlling device tobe adjusted in accordance with the displacement oi the indicating member having electrical actuating means therefor.

9. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity or light passing through said objective, means for determining'the correct exposure, comprising in combination a lightsensitive cell, indicating means fixed in position corresponding to the speed oi the shutter, movable indicating means actuatable by the cell current, manuallyactuatable means for adjusting the amount oi light falling on the cell to vary the position of the movable indicating means for enabling the fixed and movable indicating means to be brought into coincidence, and a mechanical coupling between said manually actuatable means and the diaphragm of the objective so as to enable said diaphragm to be adjusted in accordance with the displacement of the indicating means actuated by the cell current.

10. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing to said objective, means for determining the correct exposure comprising in combination a light-sensitive cell, movable indicating means having electrical actuating means therefor operatively connected to said cell so as to be capable of operation by the cell current, a second indicating means occupying a position corresponding to the setting of one of said exposure controlling devices, manually actuatable adjustable means for varying the quantity of light falling on the cell for varying the position of said movable indicating means relatively to the other indicating means and positive transmission meansconnected to said manually actuatabie means and to the other of said exposure controlling devices so as to enable the said other exposure controlling device to be adjusted in accordance with the displacement of the indicating means having electrical actuating means therefor.

11. In a portable photographic apparatus, an objective, a shutter, and a diaphragm for controlling the quantity of light passing through the objective, means for determining the correct exposure, comprising in combination a light-sensitive cell, a first indicating means actuatable by the cell current, a second indicating means occupying a position corresponding to the speed of the shutter, manually actuatable means for varying the amount of light failing on the cell ior enabling the first indicating means to be moved relatively to the second indicating means, and positive transmission means connecting the manually actuatable means to the diaphragm.

12. In a portable photographic apparatus having an objective and two exposure controlling devices, viz., a shutter and an adjustable diaphragm for controlling the quantity of light passing through the objective, means for adjusting the diaphragm to the proper setting for correct exposure including movable indicating means, a light-sensitive cell for energizing said movable indicating means, an adjustable diaphragm for controlling thequantity oi light falling on the light-sensitive cell, a manually operated indicating means operatively connected to said shutter, manually actuatable means for simultaneously adjusting the objective diaphragm and the light-sensitive cell diaphragm whereby the position of the movable indicating means is varied in accordance with the position of the manually operated indicating means.

13. The combination of a photographic camera with a photoelectric exposure meter, including a lens system, means for adjusting the opening of said lens system, a shutter, means or adjusting the speed of said shutter, and means correlating both of said adjusting means with said photoelectric exposure meter, said correlating means.

being adapted to control the reading of said exposure meter when either of said adjusting means are actuated, the said correlating means upon setting of one of said adjusting means being adapted to control the final adjustment of the other adjusting means to set up a predetermined reading in the exposure meter byboth of said adjustments.

14. In a photographic camera having an objective and two exposure controlling devices, viz., a shutter and a diaphragm for controlling the quantity of light passing through said objective, a light sensitive cell, indicating means connected to the cell and actuatable by the cell current, means for adjusting the opening of the diaphragm, means for adjusting the,speed of the shutter, means connected to and adjustable with the diaphragm adjusting means for correspondingly varying the cell current, means connected to and adjustable with the shutter adjusting means forcorrespondingly varying the cell current, whereby the indicating means actuatable by the cell current is responsive jointly to adjustment oi the diaphragm opening and of the shutter speed setting.

15. In a photographic camera in which a predetermined reading of a light sensitive device in dicates that the camera is set for proper exposure, a shutter, means for adjusting the speed of the shutter, a diaphragm, means for adjusting the opening of the diaphragm, and a light sensitive device including a measuring instrument electrically connected to a light sensitive cell for giving a reading, the reading of said device being responsive jointly to both of said adjusting means, whereby the amount of adjustment of one of said means necessary to set up a predetermined reading of said device depends upon the adjustment of the other of said means.

606: RISZDORFEF t. 

